1. Field of the Invention
The present invention relates to a software keyboard system using a touch screen, and more particularly, to a software keyboard system in which a plurality of key codes are assigned to one key, and using the trace of a stylus moving on a key displayed on a touch screen, a key code is generated, and to a method for recognizing a key code using the same. Here, "stylus" is used as a general term for any object which, when pressed onto a touch screen, can cause an input to a computer system or the like.
2. Description of the Related Art
In a small-sized personal computer (PC) such as an electronic organizer or a palm PC, it is difficult to input information. That is, since a small area of the keyboard must include a multitude of keys, the size of the key must be reduced, and thus it is difficult to rapidly and accurately input information using the keys.
To solve the above problems, software keyboards using a touch screen are being widely used.
According to U.S. Pat. No. 4,725,694 in which a central processing unit (CPU) displays an image of a complete keyboard on a screen where a touch panel is attached, the CPU recognizes the position of the touch panel pressed by a user, and operates to generate a code for a key corresponding to the position.
However, in the U.S. Pat. No. 4,725,694, since the size of the screen where the entire keyboard is displayed is small, the size of the keys is also small so that it is difficult to accurately select keys, and the surface of the typical touch panel is slippery, thereby resulting in undesired key selection.
Also, according to U.S. Pat. No. 5,612,719, the CPU displays a gesture button image on a screen where a touch panel is attached, and then the touch panel is pressed or moved on by a pen, allowing various operation modes according to the movement of the pen. That is, there are various operation modes in accordance with whether the stylus is placed on the screen or not, and whether a pop-up menu is displayed on the screen.
However, in order to select function from a pop-up menu, a two-step input process is required in which a pop-up menu is displayed, and then a desired menu is selected from the pop-up menu.